Garage Door Chain Sprocket Broke

Grasp the chain 1 foot from where it connects to the end of the threaded chain anchor.

Garage door chain sprocket broke.

Pull the chain toward the garage door and hold it in position. This is a video on how to change the gear sprockets in a craftsman garage door opener. Remove the outer nut and lock washer from the trolley threaded shaft and pull the threaded shaft out of the trolley. As a result the garage door will open a few inches and stop or it will close a few inches and reverse.

Immediate troubleshooting is required and a new garage door chain will need to be installed in place of the old one. Slide the pulley toward the garage door until the chain is stretched tight then move it toward the motor until the middle of the chain touches the upper side of the chain arm. Pull the chain off the motor unit sprocket and out of the chain spreader. This was a craftsman model 139 53976srt.

If yours is a belt drive you need a kit like this https amzn to 2zqns. This gear kit on amazon. Slide the outer trolley away from the inner trolley. Thread the nut s facing the door clockwise until it meets the bracket then release the chain.

If the sprocket is still on the top of the opener carefully remove the chain from the sprocket. Keep your fingers on the sides of the chain at least three inches away from the sprocket lift up the chain and unwrap it from the sprocket. The front sprocket is at the end of the opener rail closest to the garage door opening. The chain wraps around this sprocket as well as the gear and sprocket at the motor.

Lay the chain on the garage floor while you complete the repair. Press down on the chain with your finger. Tighten the bolts on. Another common cause for a loose chain could be the front sprocket breaking.